Aon Corporation, a provider of risk management services, insurance and reinsurance brokerage, has appointed Mark Chessher as the CFO of Aon Limited and Aon Risk Services UK.

Mr Chessher will join the company later in 2008, subject to Financial Services Authority (FSA) approval and will join the Aon Limited board. He replaces John Cullen, who earlier this year was promoted to the role of global CFO for Aon Risk Services.

Mr Chessher joins Aon from Zurich Financial Services, where he is currently the CFO of their North American corporate customer division based in New York. He is a chartered accountant and an associate of the Chartered Insurance Institute.

Peter Harmer, CEO of Aon Limited, said: Mark brings to Aon a sound knowledge of the insurance industry, along with five years of experience of interacting with the FSA. He joins us in a challenging market and at a time of change, bringing with him a set of skills and experience that are well suited to helping us successfully implement our growth strategy.